1. Udáyí Thera.-Also called Láludáyí (and Pandita Udáyí), to distinguish him from others. - He was the son of a brahmin of Kapilavatthu. He saw the power and majesty of the Buddha when the latter visited his kinsmen and, entering the Order, in due course became an arahant. When the Buddha preached the Nágopama Sutta (see A.iii.344f), on the occasion when Seta, King Pasenadi's elephant, was publicly admired, Udáyí was stirred to enthusiasm by thoughts of the Buddha and uttered sixteen verses, extolling the virtues of the Buddha, comparing him to a great and wondrous elephant. (Thag.vv.689-704; ThagA.ii.7f.; Udáyí's verses are repeated in the Anguttara (iii.346-7) but the Commentary (ii.669) attributes them to Káludáyí).
Once when Udáyí was staying at Kámandá, in Todeyya's mango-grove, he converted a pupil of a brahmin of the Verahaccáni clan and, as a result, was invited by Verahaccáni herself to her house. It was only on his third visit to Verahaccáni that Udáyí preached to her and she thereupon became a follower of the Faith (S.iv.121-4).
The Samyutta Nikáya (iv.166f.; another discussion with Ananda is mentioned in A.iv.426f) also records a conversation between Udáyí and Ananda, when Udáyí asks if it is possible to describe the consciousness, too, as being without the self. On another occasion Udáyí has a discussion with Pańcakanga on vedaná (M.i.396ff; S.iv.223-4; the Commentary SA.iii.86 and MA.ii.629 here describes Udáyí as "Pandita"). Ananda overhears their conversation and reports it to the Buddha, who says that Udáyí's explanation is true, though not accepted by Pańcakanga.
Elsewhere (S.v.86ff) Udáyí is mentioned as asking the Buddha to instruct him on the bojjhangas, and once, at Desaka (Setaka?) in the Sumbha country, he tells the Buddha how he cultivated the bojjhangas and thereby attained to final emancipation (S.v.89).
He is rebuked by the Buddha for his sarcastic remark to Ananda, that Ananda had failed to benefit by his close association with the Master. The Buddha assures him that Ananda will, in that very life, become an arahant (A.i.228).
Udáyí was evidently a clever and attractive preacher, for he is mentioned as having addressed large crowds, a task demanding great powers, as the Buddha himself says when this news of Udáyí is reported to him (A.iii.184).
According to Buddhaghosa (DA.iii.903), it is this same Udáyí (Mahá Udáyí) who, having listened to the Sampasádaniya Sutta, is beside himself with joy at the contemplation of the wonderful qualities as set forth in that Sutta, and marvels that the Buddha does not go about proclaiming them. Buddhaghosa (MA.i.526) seems to identify him also with the Udáyí to whom the Latukikopama Sutta (M.i.447ff) was preached.
2. Udáyí.-A thera. It was once his turn to recite the Pátimokkha before the Sangha, but because he had a crow's voice (kákasaraka), he had to obtain permission to make a special effort so that his recitation might be audible to the others (Vin.i.115). It is, perhaps, this same monk who is mentioned in the Vinaya as having been guilty of numerous Sanghádisesa offences (Vin.iii.110f, 119f, 127f, 137f, 135ff).
He is censured again and again and various penalties are inflicted on him, nevertheless he repeats his offences (Vin.ii.38ff). In the Nissagyiya (Vin.iii.205f) a story is told of a nun, a former mistress of Udáyí, who conceived a child through touching a garment worn by him. Once when Uppalavanná asked him to take some meat to the Buddha, he demanded her inner robe as his fees (Vin.iii.208). He seems to have been very fond of the company of women and they returned his liking. (See, e.g., Vin.iv.20, 61, 68). There was evidently a strain of cruelty in him, for we are told of his shooting crows and spitting them with their heads cut off (Vin.iv.124). He is described as being fat (Vin.iv.171). He is perhaps to be identified with Láludáyí.
3. Udáyí.-A brahmin. He visited the Buddha at Sávatthi and asked if the Buddha ever praised sacrifice. The Buddha's answer was that he did not commend sacrifices which involved butchery, but praised those which were innocent of any killing (A.ii.43f).
4. Udáyí.-See also under Káludáyí, Láludáyí and Sakuludáyí. As they are all, from time to time, referred to as Udáyí it is not always possible to ascertain which is meant. The Commentary is not an infallible guide.